An Arthrobacter citreus strain suitable for degrading ε-caprolactam in polyamide waste and accumulation of glutamic acid

Abstract

ε-Caprolactam-a toxic xenobiotic compound present in industrial polyamide waste was found to be degraded by caprolactam-degrading bacteria. Arthrobacter citreus was able to utilize up to 20 g ε-caprolactam/l as the sole source of carbon more efficiently as compared to the other Gram positive caprolactam-degrading bacteria Rhodococcus rhodochrous and Bacillus sphaericus. The cells of A. citreus remained viable in medium up to 40 g caprolactam/l. The degradation of 10 g caprolactam/l by A. citreus, when supplied as the sole source of carbon and nitrogen lead to the formation of 6-aminocaproic acid which was detected in broth and there was also an increase in the ammonium content. One of the other metabolites found to consistently accumulate in extracellular medium during the utilization of caprolactam by A. citreus was glutamic acid, though not reported in case of other caprolactam-degrading bacteria. A. citreus could metabolise caprolactam to form non toxic products such as 6-aminocaproic acid and glutamic acid which are amino acids of physiological and commercial importance. In the presence of 6-aminocaproic acid, the rate of caprolactam utilization by A. citreus was decreased but not inhibited and the viable count of cells was found to increase using both the substrates simultaneously. A. citreus was also suitable for degradation of caprolactam in presence of low phosphate as prevalent in soil, and in sterile soil without the supplementation of any other carbon or nitrogen, as well as in native non sterile soil where other microorganisms are present.

Bacterial Community under the Influence of Microplastics in Indoor Environment and the Health Hazards Associated with Antibiotic Resistance Genes

“…Arthrobacter was the second most abundant genus of Actinobacteria on PA in this study (Figure S8). Few bacteria can degrade PA, except for two strains of Arthrobacter, which grew well on PA surface and can apply PA or its monomers as carbon source. − This might explain the colonization advantage of Actinobacteria or Arthrobacter on PA in this study, which needs further verification.…”

Epsilon-Caprolactam- and Nylon Oligomer-Degrading Bacterium Brevibacterium epidermidis BS3: Characterization and Potential Use in Bioremediation

“…We have shown that the ability of Pseudomonas bacteria to utilize CAP is determined by plasmids (CAP plasmids), which carry genetic information required for the complete mineralization of the xenobiotic [ 11 , 28 ]. Later works described caprolactam-utilizing bacteria of the genera Alcaligenes , Corynebacterium , Acinetobacter , Achromobacter , Arthrobacter , Microbacterium , Bacillus, and others [ 6 , 8 , 9 , 10 , 29 ]. A phylogenetic study of CAP degraders isolated from nylon-6 production wastes attributed them to three phyla: Proteobacteria (Beta- and Gammaproteobacteria), Actinobacteria, and Firmicutes [ 7 ].…”

Multi-omics analysis reveals novel interplays between intratumoral bacteria and glioma

“…[44] Arthrobacter strain NOR5 has exhibited remarkable proficiency in facilitating the complete degradation of nornicotine[45], a direct precursor of tobacco-specific nitrosamines (TSNAs) known for their potent carcinogenic properties. [46] Furthermore, Arthrobacter citreus strains can metabolize caprolactam, thereby generating glutamate[47]-an important excitatory neurotransmitter in the central nervous system. Based on these findings, it becomes conceivable that Arthrobacter holds probiotic potential.…”